Meiosis Flashcards
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Questions and Answers

During meiosis, homologous pairs can exchange pieces of DNA after they synapse?

True

What does mitosis involve?

a single cell division, and results in two diploid cells

DNA replication occurs prior to both meiosis and mitosis?

True

What is the normal chromosome number in a human cell?

<p>46</p> Signup and view all the answers

What does completion of meiosis produce?

<p>4 haploid daughter cells</p> Signup and view all the answers

How many cells are formed in meiosis?

<p>4</p> Signup and view all the answers

What is known as the differing orientations of chromosomes along the cell equator during metaphase I?

<p>independent assortment</p> Signup and view all the answers

Meiosis II is identical to mitosis?

<p>True</p> Signup and view all the answers

During meiosis, DNA must replicate twice?

<p>False</p> Signup and view all the answers

What is the exchange of DNA between adjacent homologous chromatids known as?

<p>crossing over</p> Signup and view all the answers

What events occur during prophase I?

<ul> <li>Breakdown of nuclear envelope - Condensation of chromosomes - Movement of centrosomes</li> </ul> Signup and view all the answers

How many bivalents are formed in a cell with 20 chromosomes at the beginning of meiosis I?

<p>10</p> Signup and view all the answers

What events occur during anaphase I?

<p>separation of homologous chromosomes</p> Signup and view all the answers

At the end of meiosis I, there are two haploid cells, each with two sister chromatids per chromosome?

<p>True</p> Signup and view all the answers

By the end of which phase is the spindle apparatus fully formed?

<p>prometaphase II</p> Signup and view all the answers

Separation of ________ occurs in anaphase II of meiosis.

<p>sister chromatids</p> Signup and view all the answers

At the end of meiosis II, how many cells are formed?

<p>four haploid cells, with each chromosome consisting of a single chromatid</p> Signup and view all the answers

Replication of chromosomes occurs between meiosis I and meiosis II?

<p>False</p> Signup and view all the answers

In animal cells, cell division is accomplished by the formation of a cleavage furrow?

<p>True</p> Signup and view all the answers

What is a tetrad made up of?

<p>two homologous chromosomes, each consisting of two chromatids</p> Signup and view all the answers

Crossing over occurs during prophase I of meiosis?

<p>True</p> Signup and view all the answers

Crossing over allows the reassortment of linked genes?

<p>True</p> Signup and view all the answers

In meiosis I, the homologous pairs of chromosomes are separated when the cell divides?

<p>True</p> Signup and view all the answers

What are homologous chromosomes?

<p>chromosomes that contain the same complement of genetic information</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Gene = the functional unit of heredity which consists of a certain portion of DNA molecule Allele = similar genes on homologous chromosomes Genome = all the genes in one homologous set of 23 chromosomes in one individual</p> Signup and view all the answers

How many phenotypes are possible for the dimples trait with strict dominant-recessive inheritance?

<p>2</p> Signup and view all the answers

How many phenotypes are possible for the sickle-cell trait that exhibits incomplete dominance?

<p>3</p> Signup and view all the answers

Study Notes

Meiosis Overview

  • Meiosis involves two cell divisions resulting in four haploid daughter cells.
  • It is essential for sexual reproduction, producing gametes with half the normal chromosome number.

Meiosis Stages

  • Prophase I:
    • Nuclear envelope breaks down.
    • Chromosomes condense.
    • Centrosomes move to opposite poles.
    • Crossing over occurs, allowing genetic material exchange between homologous chromosomes.
  • Metaphase I:
    • Homologous chromosome pairs align along the cell equator.
    • Independent assortment creates varied gametes.
  • Anaphase I:
    • Homologous chromosomes separate and move to opposite poles.
  • Telophase I:
    • Two daughter cells form; each cell is haploid but contains two sister chromatids per chromosome.

Meiosis II

  • Similar to mitosis, involving separation of sister chromatids.
  • Prophase II:
    • Spindle apparatus forms.
  • Anaphase II:
    • Sister chromatids separate and move to opposite poles.
  • Telophase II:
    • Four haploid cells result, each with chromosomes consisting of a single chromatid.

Key Concepts

  • Homologous chromosomes: Chromosomes with the same genetic information but may carry different alleles.
  • Tetrad: Composed of two homologous chromosomes, each with two sister chromatids, formed during Prophase I.
  • Crossing over: Exchange of genetic material between adjacent homologous chromatids enhances genetic variability.

Genetic Principles

  • Gene: The functional unit of heredity consisting of DNA.
  • Allele: Variants of a gene located at the same position on homologous chromosomes.
  • Genome: The complete set of genes in one individual.
  • Inheritability:
    • Dominant-recessive traits (e.g., dimples) result in two phenotypes.
    • Incomplete dominance (e.g., sickle-cell trait) allows three phenotypes.

Important Facts

  • Human cells typically contain 46 chromosomes (23 pairs).
  • DNA replication occurs before meiosis I, not between meiosis I and II.
  • At the end of meiosis II, each of the four haploid cells has a distinct combination of genetic material due to crossing over and independent assortment.

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Description

Test your knowledge of meiosis with these flashcards. This set includes true or false questions and definitions related to meiotic processes and their differences from mitosis. Ideal for studying biology concepts related to cell division.

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